A receding horizon sliding control approach for electric powertrains with backlash and flexible half-shafts

Active control of electric powertrains is challenging, due to the fact that backlash and structural flexibility in transmission components can cause severe performance degradation or even instability of the control system. Furthermore, high impact forces in transmissions reduce driving comfort and possibly lead to damage of the mechanical elements in contact. In this paper, a nonlinear electric powertrain is modelled as a piecewise affine (PWA) system. The novel receding horizon sliding control (RHSC) idea is extended to constrained PWA systems and utilised to systematically address the active control problem for electric powertrains. Simulations are conducted in Matlab/Simulink in conjunction with the high fidelity Carsim software. RHSC shows superior jerk suppression and target wheel speed tracking performance as well as reduced computational cost over classical model predictive control (MPC). This indicates the newly proposed RHSC is an effective method to address the active control problem for electric powertrains.     

公共电动自行车系统运营模式设计模型

当前对传统公共自行车系统运营模式的研究主要是定性分析,各种方法标准不一,且研究结论与实际差别较大,不能直接用于资金、设施等要求更高的公共电动自行车系统的运营模式设计问题.因此,提出了一种定量设计模型,利用0-1混合整数规划模型对系统的经营主体进行筛选,再利用动态规划模型分配资源.利用算例进行模拟分析,结果表明:①与以资金多和收益好为优的常规的定性分析法相比,定量模型能更合理配置系统构成要素,降低政府的财政负担,分别为政府节省18.68%和23.09%的资金.②在公共电动自行车系统建设和运营过程中,宜采用政企合作模式.③相对于系统运营而言,系统建设期间对政府投入的资金反应更灵敏,因此政府有必要加大建设期的资金投入.     

A study of jack-up leg drag coefficients

The accurate prediction of drag coefficients for truss-type jack-up legs is an important part of a unit's design. Over the past 14 years, a series of windtunnel tests have been conducted on both square and triangular cross-section leg configurations. A calculation method which closely fits the model test data has also been adopted. A previous paper described the early testing and the MMEC calculation method for square legs. Since then, testing and research have continued on both square and triangular leg designs. This paper describes the more recent testing performed on square legs, and it details the testing and the MMEC method for triangular legs. In addition, the effects of cornerpost design and surface roughness are discussed. Several example calculations are provided in Appendices.     

Transportation — “Current on-board vehicle systems”

The paper reviews the current situation on-board microprocessor applications. It first describes the aspects of vehicle technology and performance that are the focus for on-board computing equipment, from engine management systems through to fully intergrated driver decision support. In the second section a wider perspective is taken by examining the interaction of the vehicle and its environment. The third and final section of the paper considers elements of communication which permit extensive transmission of vehicle and journey data for public and private use. The conclusion identifies factors which will influence the speed with which further applications will be adopted.     

Effect of parking information on travelers' knowledge and behavior

In many urban centers the demand for parking increases sharply before Christmas mainly due to shopping activity — causing parking congestion. One way to ameliorate such congestion is by disseminating parking information. Informed drivers may divert to relatively under-utilized parking facilities relieving the pressure on congested facilities. The City of Nottingham in England tested a real-time parking information system designed to alleviate congestion in the City Center parking facilities. Real-time information was disseminated through the radio, while historical information regarding parking locations was disseminated through newspaper advertisements and leaflets. The objective of this study is to assess impacts of the parking information system on travelers' knowledge and decisions.Survey research was used to understand traveler response. Respondents' levels of knowledge regarding car parks were analyzed by developing Poisson regression models. Drivers were more likely to have greater knowledge of city center car parks if they used several information sources (radio broadcasts, newspaper advertisements or leaflets and word-of-mouth), were active seekers of parking information, and searched for parking rather than going directly to a parking facility. In addition, the study of behavior showed that drivers were more inclined to use the relatively under-utilized Park-and-Ride facilities instead of the city center car parks if they received parking information from Newspaper advertisements/leaflets. Overall, the parking information service in Nottingham was effective; it seems reasonable to establish such information dissemination and monitoring systems at parking facilities in other urban areas. Furthermore, to support informed travel and activity participation decisions, parking information should be integrated with traffic and transit information.     

综合安防集成管理平台研究

详细介绍了综合安防集成管理平台的功能要求、特点及实现方法,同时描述了各主要子系统的功能,充分体现了安防集成管理平台的网络化、模块化及高度安全性、开放性、扩展性和易用性。     

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作者回顾了钱学森院士回国后在国防科工委创建中国的“两弹一星”的同时,在中国开创了系统科学与系统工程学科.介绍了北京交通大学一批交通运输学科教师在深入学习钱老的学术思想和系统工程学术理论的基础上,进行系统运输科学与系统工程学科的融合,并于1989年提出了建立中国的“交通运输系统工程”新学科的设计.论文介绍了“交通运输系统工程”学科开创2。多年来取得的12项重要成果.其中最重要的有3项:l.在北京交通大学建立了交通运输系统工程硕士学位、博士学位学科点,开始培养中国第一批交通运输系统工程专业硕士、博士以及博士后研究生的进程;2.交通运输系统工程学术团队如何在“中国系统工程学会”的支持下,组建了“中国系统工程学会交通运输系统工程专业委员会”;3.在中国科协和中国系统工程学会的支持下,创建了《交通运输系统工程与信息》杂志论文高度评价了钱老回国对中国学科建设的深远影响,以及如何将交通运输学科与钱学森院士的学术思想紧密结合而创造了新学科——交通运输系统工程学科.     

自升式风电安装船桩腿强度分析和优化

近年来,随着国内海上风电行业的蓬勃发展,市场对自升式风电安装船的需求日益迫切。桩腿是影响自升式风电安装船作业安全性的关键环节,桩腿设计也是自升式风电安装船的关键技术难点之一;而海上风电场的选址逐渐向离岸更远、水深更大的方向发展,客观上也对桩腿适应更恶劣海况条件的能力提出了更高要求。本文结合近年来多型自升式风电安装船桩腿设计经验,分析研究了桩腿总强度计算和优化的过程,及其与海况环境、作业条件、可变载荷等参数之间的相关性,为自升式风电安装船的桩腿设计提供了有效方法。     

石河子独塔斜拉桥横向抗震合理约束体系研究

以石河子独塔斜拉桥为工程背景,建立有限元抗震模型,采用非线性动力时程分析方法对该桥进行罕遇地震作用下的横桥向抗震分析。为研究横向约束体系对独塔斜拉桥抗震性能的影响,主塔处分别采用塔梁固结、塔梁分离、塔梁铰接、竖向支承、竖向支承加弹性索、竖向支承加黏滞阻尼器(FVD)等不同横向约束形式、边墩处分别采用横向铰接、竖向支承、铅芯支座、竖向支承加黏滞阻尼器等不同约束形式进行抗震计算,通过分析对比,得出以下结论:若边墩受力不控制设计,则主塔处采用竖向支承加黏滞阻尼器、边墩横向铰接是相对最优的约束体系;若边墩受力控制设计,则主塔处采用竖向支承加弹性索、边墩设置铅芯支座是相对最优的约束体系。     

高速铁路接触网风致振动与风偏的动态计算方法

利用ANSYS软件建立接触网弹链、简链风致响应有限元模型,从导线弛度、张力及弹性角度,验证有限元模型的准确性;采用谐波合成法(WAWS)模拟针对接触网结构特点的脉动风场;计算系统在风荷载作用下的动态响应,利用空气动力学理论计算接触网平均位移,采用时程分析方法计算接触网动态位移,并将二者叠加得到接触网风致响应总位移。通过开展接触网气动弹性风洞试验,结果表明:提出的基于有限元的风致振动与风偏的动态计算方法与风洞试验结果基本吻合;该方法计算结果准确,具有较好的工程应用价值。